Can not send a iMessage to just one iPhone contact
My husband and I both have iphoneX I can not send a iMessage to him from my phone. I also have the iPad mini 6 and from there I can not send him any messages. I can send iMessages to all my other contacts with iPhones as well as my iPad. We are both up to date with iOS and have rebooted both of our phones and my iPad. I do not have him blocked and I have SMS on as well as iMessage on my devices. I can send him a regular text from my phone only. Is there something else I need to do on either of our phones?
iPhone X